Kněžičky NNR was established in 2006. However, the majority of the territory had been protected since 1948 as the Žehuňská obora (game preserve) and Žehuňský rybník (fishpond) Nature Reserve and as the Bludy Nature Reserve since 1983. The NNR covers an area of 89 ha. The subjects of the protection are the thermophilous oakwoods with a high proportion of old trees, themophilous steppe and forest steppe communities on a marlstone substrate, early succession communities on the exposed areas of marlstones after erosion on the steepest slopes, areas with subhalophilous communities in terrain depressions on impermeable substrates on the lower part of the slope and the endangered plant and animal communities which are bound to these specific habitat types. The territory is included in the Žehuňský rybník – obora Kněžičky SPA – Bird Area and the proposed Žehuň – Obora Site of Community Importance.
The NNR lies on the border of the Středočeský kraj - Central Bohemian Region and Královéhradecký kraj - Hradec Králové regions on the south-facing slopes of the Hradčanská Questa above the Žehuňský rybník fishpond and lies at elevations between 200 and 260 metres above sea level. The geological substrate is built of Cretaceous calcareous sandstones, marlstones and calcareous claystones which contain many fossils. So-called “white slopes” form here – areas with exposed bedrock after landslides have carried the soil away. Where there is soil cover it is most often pararendzina or lithosol. On the impermeable substrate on the lower slopes gleysol is typical and small areas are also covered with cambisol and brown soils. The NNR lies in a warm climatic region.
Approximately one third of the NNR is forest covered with the unusually tree-sized white oaks (Quercus pubescens). The forest stands with a high proportion of old trees and dead wood, which are within the Kněžičky game preserve are the biotope of rare xylophagous insects such as red click beetle (Elater ferrugineus), stag beetle (Lucanus cervus), the flower beetle (Cetonischema aeruginosa) and others. These forest stands are lacking in younger trees and the herb layer is also rather poor. The forest stands which lie outside of the game preserve have a much more varied vertical structure and a well developed herb layer with the dominant purple gromwell (Lithospermum purpurocaeruleum). A few examples of lady orchid (Orchis purpurea) can also be found here.
Another significant part of the reserve contains xerothermophilous grasslands. Part of the grasslands which are inside the game preserve were previously maintained only as grazing for the game animals which were kept here. The predominant species here is the tor-grass (Brachypodium pinnatum). The population of yellow pheasant’s eye (Adonis vernalis) numbers several thousand plants. Other interesting species which grow here are the mugwort Artemisia pontica, fringed gentian (Gentianopsis ciliata), lesser meadow-rue (Thalictrum minus) and cut-leaved self-heal (Prunella laciniata). At the base of the slope, where soil accumulates after landslips, small waterlogged depressions have formed on the impermeable substrate where fen species can be found, including the moor-grass Sesleria uliginosa, water germander (Teucrium scordium) and adderstongue (Ophioglossum vulgatum). The early succession stages of the exposed bare slopes are also of interest and the dominant species here is the dwarf sedge (Carex humilis). The grasslands outside the game preserve were mostly maintained by hand cutting but were then abandoned for many years, which resulted in the expansion of shrubs into these biotopes. The dominant species here is Irish fleabane (Inula salicina), along with rich populations of the dwarf gentian - Gentianella amarella subsp. amarella and goldilocks aster (Aster linosyris), snowdrop windflower (Anemone sylvestris) and others. The fungi populations are also of interest and we can find larger umbers of the rare thermophilous devil’s bolete (Boletus satanas) here.
A notable butterfly is the dryad (Minois dryas), which has one of its strongest populations in the Czech Republic at Kněžičky NNR. A notable bird which nests in the shrub growths is the barred warbler (Sylvia nisoria).
Approximately half of the Kněžičky NNR lies in the game preserve of the same name, which was set up in 1611 to breed fallow deer and mouflon. Grazing in the preserve has the negative consequence of preventing natural renewal of the forest stands, but on the other hand grazing helps to maintain the xerothermophilous grasslands in the preserve. The forest stands were cut for timber in the past and were degraded in some areas by overcutting or replanting with trees which are not suitable from a geographical or locality view point.
The steppe biotopes were used in the past as orchards and many old and disintegrating fruit trees, of varieties which are no longer grown still stand here. The NNR is not open to tourists. Entry to the game preserve is forbidden all year round.